- Pregnancy, attempting pregnancy, or unwillingness to use medically acceptable contraception for entire study period if sexually active. Women of childbearing potential will have serum pregnancy testing. Women who are menopausal (over 50 years of age with no menses for more than one year) or surgically sterilized are not considered of child-bearing potential and will not require pregnancy testing or contraception. Acceptable contraception includes: condoms/spermicide, prescription hormonal contraceptive pills, patches, rings, and implants; IUDs.